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Journal of the American College of Cardiology
© 2005 by the American College of Cardiology Foundation
Published by Elsevier Inc.
Vol. 46, No. 1, 2005
ISSN 0735-1097/05/$30.00
doi:10.1016/j.jacc.2005.04.017
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The Coronary Venous Anatomy
A Segmental Approach to Aid Cardiac Resynchronization Therapy
Jagmeet P. Singh, MD, PHD,* Stuart Houser, MD,† E. Kevin Heist, MD, PHD,* Jeremy N. Ruskin, MD*
Boston, Massachusetts
The coronary sinus is the gateway for left ventricular (LV) epicardial lead placement for
cardiac resynchronization therapy. The implanting electrophysiologist is usually challenged by
a high degree of variability in the coronary venous anatomy, making it important to have a
more consistent and uniform segmental approach to describe the coronary venous tree and its
branches. Classifying the coronary sinus branches and tributaries by the segment of their
location rather than by conventional anatomic names (i.e., middle cardiac vein, great cardiac
vein, and so on), would provide more relevant anatomic and functional information at the
time of LV lead placement. This would enable the implanting physician to proactively
correlate the venous anatomy with the segmental wall motion abnormalities or dyssynchrony,
as defined by echocardiography and other imaging modalities. The current viewpoint calls for
a more systematic segmental approach for describing the coronary venous anatomy. (J Am
Coll Cardiol 2005;46:68 –74) © 2005 by the American College of Cardiology Foundation
The cardiac venous system, which has always been
overshadowed by the proximate presence of the coronary
arterial tree, has recently begun to attract more attention.
Its role in invasive cardiology has been directed at either
targeted drug delivery (1) or retrograde cardioplegia
administration (2). Of late, there has been increasing
interest in the role of the cardiac venous system, toward
providing a potential conduit to bypass coronary artery
stenosis (3) and to delivery of stem cells to infarcted
myocardium (4).
In the arena of electrophysiology, the cardiac venous
system has always been of strategic interest. Coronary
sinus cannulation has allowed access to the left atrial and
left ventricular (LV) epicardium, enabling a spectrum of
diagnostic and mapping maneuvers to aid in the determination of the type of arrhythmia as well as permit the
delivery of ablative energy (5,6). More recently, the
coronary sinus has become the gateway to LV epicardial
lead placement to achieve biventricular pacing. The
recent surge in the number of implanted biventricular
pacemakers and defibrillators stems from numerous studies that have clearly shown the significant benefit provided by cardiac resynchronization therapy in patients
with congestive heart failure (7,8). To achieve this
therapeutic goal, it is critical that the LV epicardial lead
be positioned appropriately in the region with delayed
electrical activation and mechanical dyssynchrony (9). So
far, the approach for lead positioning has been rather
From the *Cardiac Arrhythmia Service and the †Cardiac Pathology Service,
Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
This work was funded in part by the Clinical Investigator Training Program Award
(supported by Harvard University and Massachusetts Institute of Technology).
Potential conflicts of interest: Dr. Ruskin (Medtronics, Inc., consultant/advisor); Dr.
Singh (Guidant Corporation, consultant/advisor).
Manuscript received December 14, 2004; revised manuscript received March 23,
2005, accepted April 5, 2005.
simplistic and has been mostly directed at placement of
the lead along the lateral wall of the LV (10). Recent data
have suggested that mechanical asynchrony is variable
and that a simplistic approach may not always provide the
maximal hemodynamic benefit. The optimal site for LV
lead implantation may vary depending on the region
and/or extent of dyssynchrony (11,12). Transvenous LV
lead placement is dependent on the availability of a vein,
and because of the variable coronary venous anatomy,
there may not always be a suitable major vein in the
region of interest that can accommodate a pacing lead
with acceptable pacing parameters.
Conventional coronary venous anatomy has primarily
focused on the site of origin of various venous branches
from the main body of the coronary sinus rather than the
particular segment of myocardium that a particular vein
or venous tributary overlies. Although this conventional
anatomic classification remains important, the great variability in the course of coronary veins and tributaries
makes it difficult to directly correlate conventional coronary venous anatomy with specific regions of the underlying LV.
In the present review of the coronary venous anatomy and
its variability, this report highlights the need for a segmental
classification to map the coronary veins and tributaries in
relation to the LV wall in a manner comparable to that of
echocardiography and LV angiography. This stresses the
need for an organized practical approach to coronary sinus
angiography (similar to that of coronary arteriography),
with careful attention being paid to the tributaries of main
venous branches and emphasis put on their course and
dimensions to facilitate LV lead placement. This classification system attempts not to supplant but rather to add
information to the conventional coronary venous anatomic
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July 5, 2005:68–74
Abbreviations and Acronyms
CT ⫽ computed tomography
LV ⫽ left ventricle/ventricular
nomenclature, which is of particular relevance to the invasive cardiologist and electrophysiologist.
CONVENTIONAL CORONARY VENOUS ANATOMY
Based on the region being drained, cardiac veins can be
grouped into the following: 1) the coronary sinus and its
tributaries, which return blood from almost the whole heart;
2) the anterior cardiac veins, which primarily drain the
anterior regions of the right ventricle and the right cardiac
border; and 3) the thebesian veins (venae cordis minimae),
which open directly into any of the four chambers. Although the coronary sinus invariably lies in the atrioventricular groove, its branches and their locations are far more
variable than the those of the coronary arterial system
(13,14). The coronary sinus opens into the right atrium
posteromedially, with its opening being guarded by the
highly variable thebesian valve, which can hinder cannulation of the coronary sinus os (15). The coronary venous
system can be considered as first-order tributaries originating from the main coronary sinus (i.e., the small, great,
posterior, and middle cardiac veins), which then branch into
second- and third-order tributaries (Fig. 1). The anterior
interventricular vein ascends in the anterior interventricular
sulcus (parallel to the left anterior descending coronary
artery) from the apex toward the base of the heart and ends
in the great cardiac vein. It then turns laterally at the base of
the heart along the left atrioventricular groove (parallel to
the left circumflex coronary artery) and wraps around the
left side of the heart, going posterior to merge with the
coronary sinus. In addition to several smaller tributaries
from the left atrium and ventricles, the great cardiac vein
receives two main branches, namely the large left marginal
vein, along the lateral border of the heart, and the posterior
LV branch (also known as the posterolateral branch). The
great cardiac vein terminates in the coronary sinus, a
junction defined by the presence of the left atrial oblique
vein. This transition point is usually marked by the presence
of intravenous valves, which can obstruct catheter and lead
placement. Another important branch is the middle cardiac
vein, which runs in the posterior interventricular grove,
parallel to the posterior descending coronary artery.
Of all of the branches of the coronary venous system, the
great cardiac and middle cardiac vein are the two most
consistently present branches (16). Unlike the middle cardiac vein, the great cardiac vein varies considerably in its
course (17,18). Lateral and posterior venous branches together are seen in ⬍50% of human hearts, unlike the
anterior interventricular and middle cardiac veins, which are
seen in more than 90% (19). Although Ortale et al. (13)
have indicated that the left marginal vein may vary in its
Singh et al.
Coronary Venous Anatomy
69
course in relation to the lateral wall of the heart and drain
either into the great cardiac vein (81%) or into the coronary
sinus (19%), this may not be definitive (20). Implantation of
the coronary sinus lead usually involves the lateral and
posterior branches, which are quite variable in their number,
tortuosity, dimensions, and angulation with respect to the
main trunk of the atrioventricular venous ring (16).
The coronary sinus is the most constant feature of the
cardiac venous system, although several congenital anomalies have been described (21). There is also a high degree of
variability in the number of branches between the middle
cardiac vein and the anterior interventricular vein. Other
variable features of the coronary venous anatomy include the
presence of ostial valves of the cardiac veins (Vieussens
valves), inter-branch collateralization, and intramural versus
epicardial course, all of which may significantly impact
selection and cannulation of a cardiac vein, as well as the
stability and pacing threshold of an implanted lead.
This conventional anatomic classification of the coronary
venous tree is limited by the large variability in its branches
and their course across the epicardial surface of the heart.
Lately, because of the increased need to identify LV veins
for lead implantation, there has been a resurgence of interest
in the anatomic variations of the cardiac venous circulation.
Figure 1. Coronary sinus angiogram of a cadaveric human heart. This
heart is splayed out in an anterior view to show the entire length of the
atrioventricular venous ring on the left side of the heart. The dotted lines
depict the near-equal segmental divisions along the horizontal (short) axis.
The horizontal line extends from the coronary sinus ostium (origin of
MV) to the point where the AV terminates into the great cardiac vein.
Each of the segments are defined as follows: A ⫽ anterior segment; B ⫽
lateral segment; C ⫽ posterior segment. The segment refers to the region
under the respective letters A, B, and C. Conventional branches are labeled
as follows: AV ⫽ anterior interventricular vein; LV ⫽ lateral marginal vein;
PV ⫽ posterior cardiac vein; MV ⫽ middle cardiac vein. This figure
highlights the second- and third-order tributaries and collateral circulation.
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Figure 2. Coronary sinus angiogram of a cadaveric human heart. This is a
vertical-axis (longitudinal) look at the heart. The dotted lines depict the
segmentation of the heart into three equal parts, i.e., the basal, mid, and
apical regions. This is a lateral view showing the area between the lateral
marginal vein (LV) and the anterior interventricular vein (AV).
Previous attempts to categorize different patterns have
ascribed more importance to variations in the direction of
drainage rather than the presence or absence of the abovementioned tributaries and their branches. What is most
important for the invasive electrophysiologist is a classification system that is simple and is directed primarily at
identifying the LV site underlying a particular vein or
tributary.
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system reflect the entire zone that may be approached by LV
leads implanted via the coronary sinus, but excludes the
ventricular septum. It is bordered superiorly by the main
body of the coronary sinus, anteriorly by the anterior
interventricular vein, posteriorly by the middle cardiac vein,
and inferiorly by the apex of the LV.
According to this classification system, the anterior interventricular vein will always lie in an anterior position and
the middle cardiac vein will always lie in a posterior
position, with both major veins coursing from base to apex.
Although the middle cardiac vein typically originates from
the coronary sinus, occasionally it has a separate ostium.
Various branches originating from the main body of the
coronary sinus can be classified as anterior, lateral, or
posterior according to their site of origin. The course of the
tributaries can be further described as coursing medially or
laterally, away from main branches in the anterior and
posterior segments or anteriorly or posteriorly from main
branches in the lateral wall segment (Figs. 1 and 3).
Importantly, this approach identifies the course of these
veins and their tributaries across the LV epicardial surface.
In this way, a particular branch can be described both by
conventional nomenclature (i.e., a branch from the middle
cardiac vein . . .) and by segmental classification (i.e., . . . a
second-order tributary of the posterior segmental branch
that courses across the lateral region of the LV at the
SEGMENTAL CLASSIFICATION
Classifying the regions of drainage of the coronary venous
system in a segmental manner will appropriately help to
identify and match the location of the left-sided cardiac
venous tree to the underlying LV myocardial segment. This
correlation is important from the electrophysiological aspect
because it will allow a more precise positioning of the LV
lead for enhancing cardiac synchrony. This method of
classification separates the left-sided cardiac veins according
to a horizontal (short) axis, a vertical (longitudinal) axis, and
the course of the tributaries.
Along the horizontal (short) axis, the atrioventricular
venous ring from the coronary sinus ostium to the anterior
interventricular groove can be divided into three equal
segments: anterior, lateral, and posterior (Fig. 1). Subclassification along the longitudinal axis (from base to apex)
refers to the origin of second-order tributaries and also
incorporates three zones: basal, mid, and apical (Fig. 2).
This classification creates nine segments of the LV in a 3 ⫻
3 grid, which is comparable to that described by other LV
imaging modalities. The regions of the LV described by this
Figure 3. Coronary sinus angiogram in a patient with ischemic cardiomyopathy (right anterior oblique 30° view). This angiogram highlights lateral
segmental branch and the multiple second-order tributaries originating in
the basal (B), mid (M), and apical (A) regions, coursing in the anterior
(apical branch) and posterior direction (i.e., branches from the basal and
mid-region). LV ⫽ lateral marginal vein; GV ⫽ great cardiac vein; AV ⫽
anterior interventricular vein.
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mid-ventricular level). These two pieces of information are
complementary; they both describe how to access a region
(i.e., via the middle cardiac vein) and describe the region in
relation to the LV epicardium (i.e., the mid-lateral LV).
Classification in this way will provide maximal information
to the invasive cardiologist and electrophysiologist attempting to use the coronary venous system to access specific
regions of the LV. This is also advantageous especially in
circumstances in which there is no conventionally named
major venous branch in the region of interest. The segmental approach is also of value when trying to cross-reference
the venous anatomy to the LV segment with maximal
dyssynchrony. This approach also emphasizes the importance of recognizing the presence of second- and thirdorder branches, which may course over the lateral wall and
serve as a good site for lead placement, especially in the
absence of a first-order lateral branch.
CORONARY VENOUS IMAGING
Retrograde venography via conventional balloon occlusion
angiography has enabled the delineation of the number and
caliber of the large venous branches (16). This technique
requires central venous access and cannulation of the coronary sinus. Unlike anterograde coronary arteriography, coronary venography is often limited by the vigorous backwash
of the injected contrast, which impairs the ability to define
the detailed anatomy of the tributaries and collateral circulation. Cardiac venous angiography, like coronary arteriography, must be systematic with appropriate fluoroscopic
angulations to clearly define the second- and third-order
tributaries for coronary sinus lead implantation. Although
the posterior and lateral branches are usually first choices for
lead placement, their presence, position, and size is variable.
Therefore, it is also important to define second-order
tributaries from the anterior and posterior segmental veins
(inclusive of the anterior interventricular vein and middle
cardiac vein), which cross laterally over the myocardial
segment of interest. This segmental approach also calls for
a more systematic approach to cardiac venous angiography.
Coronary venous angiography performed in at least two
different views with the necessary caudal or cranial angulations to separate the branches and display the course of the
main branches is key to the segmental approach. Patients
receiving cardiac resynchronization therapy devices have an
underlying cardiomyopathy and may have had extensive
remodeling and rotation of the heart. Importantly, the
interventricular septum can be consistently profiled by
delineating the middle cardiac vein (posteriorly) and the
anterior interventricular vein (anteriorly) branches. Using
these as reference veins, the lateral wall venous branches can
be profiled by individualizing the different radiologic views
(with craniocaudal angulations). Sub-selective angiography
of the main branches is often important to clearly define the
pattern of distribution of the second- and third-order
tributaries.
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Coronary Venous Anatomy
71
The transverse diameter of the epicardial veins remains
constant during systole and diastole, with flow occurring
as a bolus during each cardiac cycle. Therefore, uniform
opacification of the entire cardiac venous system including tributaries is difficult with a single bolus of contrast
delivered at the proximal end (22). To address this
problem, better catheterization and more systematic angiographic techniques are currently being developed.
Newer investigational angiographic techniques with a
double balloon occlusive approach can specifically isolate
the branch and tributaries of interest in a particular
segment (Fig. 4). These branches play a key role in
positioning the guidewires for support and LV lead for
pacing during the implantation procedure. Furthermore,
because there may be no first-order lateral segment
branches, it is important to recognize second-order tributaries from the anterior and posterior segment branches,
which may course over the desired segment of interest.
As seen in Figure 3, the second-order tributaries originating in the basal, mid, and apical third of the lateral
segmental branch course both anteriorly and posteriorly,
providing several sites for lodging the lead. Notably, the
dimensions of the coronary sinus and its tributaries are
directly affected by the LV end-diastolic pressure and
may differ considerably between patients with cardiomyopathies that differ in severity and duration.
Figure 4. Volume computed tomography image of the coronary veins in a
cadaveric heart. Double balloon occlusive venography was performed to isolate
the lateral segment of the coronary venous tree. The lateral vein (LV) and its
tributaries can be seen in great detail. 1 ⫽ the LV, which is the first-order
tributary; 2 ⫽ second-order tributary; 3 ⫽ third-order tributary.
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Recent developments in rotational contrast venography
(Allura FD 10) offer a dynamic multi-angle visualization
of the coronary venous tree. The coronary sinus angiograms can be obtained using a 4-s isocentric rotation of
the imaging camera over a 110° arc. The rotational
images can then be reviewed over a full range of angles,
providing the operator with considerably more information about the coronary venous tree and its branches than
standard images. Also, three-dimensional models of the
venous tree can be reconstructed (Figs. 5A and 5B) to
give more information regarding the size of the coronary
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sinus, its main branches, and the second-order tributaries. This information should prove useful both to define
an individual patient’s coronary venous anatomy and to
tailor an LV lead implant strategy that targets a myocardial segment of interest.
Electron beam computed tomography (CT) and multidetector row CT enable three-dimensional reconstruction
of tomographic images of the beating heart and provide a
detailed, minimally invasive definition of the coronary
venous anatomy (19,23). Unlike retrograde venography, CT
angiography allows for simultaneous imaging of the coro-
Figure 5. Rotational venous angiogram, with still frames in anteroposterior (A) and left anterior oblique 30° (B). PV ⫽ posterior vein; MV ⫽ middle cardiac
vein; GV ⫽ great cardiac vein; AV, anterior cardiac vein. Alongside are three-dimensional reconstructed images of the coronary venous tree, facilitating
segmental visualization of the coronary venous anatomy. The coronary venous ring is divisible into three segments: posterior (C), lateral (B), and anterior
(A), in both views. (B) The mid-ventricular position of a lateral segmental branch (1), closely corresponding to the second-order lateral tributary from an
anterior segmental branch, extending over the mid-ventricular region (2).
Singh et al.
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nary arteries and allows for assessment of arteriovenous
relationships (Fig. 6). A comprehensive CT evaluation of
the coronary venous anatomy of a patient before implantation of a cardiac resynchronization device could help to
determine the suitability of the patient for transvenous LV
pacing from a known venous tributary over the desired
location before an invasive procedure is undertaken. Such
minimally invasive imaging may thus facilitate the prediction of technical difficulty, selection of appropriate equipment, and identification of the venous tributary with an
appropriate diameter in the region of interest. As of yet this
approach has not been tested prospectively, and may be
limited in some cases by difficulty in visualizing second- and
third-order tributaries in sufficient detail. As a disadvantage,
current CT technology requires at least 60 ml of contrast,
which would be an additional dye load to the 10 to 40 ml
required for the intraprocedural retrograde venogram. In
addition, the effective radiation dose received from a CT
coronary venogram is approximately 9 to 11 mSv (24).
Advances in magnetic resonance imaging may allow this
imaging modality to be used in a similar manner in the
future. Real-time integration of coronary venous (segmental) branch location with echocardiographic or magnetic
resonance imaging-guided measurements of LV segmental
dyssynchrony, along with improvement in LV lead technology, will significantly influence our approach to treating
patients with heart failure and ventricular dyssynchrony.
73
CONCLUSIONS
This paper calls for a more systematic approach to detailing
the LV regions supplied by branches of the coronary venous
system. The high degree of variability in coronary venous
anatomy makes it important to have a uniform segmental
classification system for approaching these vessels. It will be
useful to the electrophysiologist to classify coronary sinus
branches and tributaries by their epicardial location in
addition to their anatomic classification. Correlating the
venous anatomy with the segmental wall motion abnormalities or dyssynchrony, as defined by echocardiography and
other imaging modalities, may provide more relevant anatomic and functional information at the time of LV lead
placement.
Future approaches to epicardial lead placement may
involve a noninvasive preprocedural definition of the coronary venous anatomy, followed by more selective angiographic techniques to enable better definition of the venous
anatomy for LV lead placement. Further recognition of the
venous tributaries in terms of their distribution, angulation,
tortuosity, and dimensions will enable the development of
lead positioning tailored to each individual patient. This will
allow for translation of current advances in our understanding of regional mechanical dyssynchrony into the clinical
practice of LV lead implantation.
Acknowledgments
The authors thank Volker Rasche (Philips Medical Systems) for his assistance with the three-dimensional reconstruction of the coronary venous tree from the rotational
venogram.
Reprint requests and correspondence: Dr. Jagmeet P. Singh,
Massachusetts General Hospital, Cardiac Arrhythmia Service,
GRB 109, 55 Fruit Street, Boston, Massachusetts 02114. E-mail:
[email protected].
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Figure 6. Standard multidetector computed tomography angiogram (Brilliance 16P scanner) delineating the coronary venous branches in close
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branches are labeled as follows: LV ⫽ lateral marginal vein; MV ⫽ middle
cardiac vein; CS ⫽ coronary sinus; PDA ⫽ posterior descending coronary
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